Thought I'd give a quick little rundown on what all is needed and how to install shaders for Minecraft. This will be written under the assumption that you're running 1.7.2. While it is possible to run in 1.7.4 and 1.7.5, I personally haven't tried. MCP (core code that most Mods are based off of) hasn't been updated for those versions yet and the mods I use have thusly not been updated.
The first thing you'll need is Forge. The easiest method is to download the "Installer-Win" version, which will download an .exe file. Double-click the file and let it do it's thing. Once it's done, go ahead and launch Minecraft to run/test once with the new profile. Click on "Edit Profile", click the "Use version" dropdown and select the "release 1.7.2-Forge10.12.0.xxxx" where xxxx is the version that you downloaded. I've tested/run with version 1057 without issue. Click "Save Profile" and go ahead and login to ensure the game doesn't crash. If it does crash, you're on your own.
Shaders Mod (GLSL)
The next think you'll need is the actual shader mod. Download the 1.7.2 file and place in your .minecraft/mods subfolder. It won't actually get listed in-game via the "Mods" button.
Sonic Ether's Unbelievable Shaders (SEUS)
Lastly you'll need an actual Shader pack. There's quite a few available linked in the GLSL thread. I personally prefer SEUS. The newest version (10.1 Preview 2 as of 4/9/2014) is just downright gorgeous. It has a few minor bugs (flowers and wheat don't currently sway even when enabled) but makes up for it with volumetric clouds and fog/puddles when it rains. Once you download the file, create a subfolder under .minecraft called "shaderpacks". Extract SEUS underneath this folder (ensure to extract with folder hierarchy). You should end up with a folder structure like ".minecraft/shaderpacks/SEUSsomethingsomething/shaders". Ensure that underneath the "shaders" subfolder that you have a listing of various ".fsh" and ".vsh" files.
Relaunch Minecraft and log in. You should now have a "Shaders..." button in your Options menu where you can enable SUES. Enjoy the gorgeous graphics.
By default, I believe leaf swaying is disabled (it does have a pretty decent performance impact if enabled) that you can enable by going to the "shaders" subfolder and modifying the gbuffers_terrain.vsh file. Look for a "//##define WAVING_LEAVES" entry and remove the "//".
If you run into any issues, feel free to ask. As a side note, I also recommend running Java 1.8 (http://www.oracle.com/technetwork/java/javase/downloads/jre8-downloads-2133155.html)
If you want to get some added depth effect to your blocks, you can generate what are called Normal Maps which essentially define the actual surface of the block so that the light interacts accordingly. Rather than re-write a how-to on that, I'll just recommend following this guide: http://imgur.com/gallery/R1Q3L
Edited by kagato on April 9, 2014 at 14:56:05
Chuck Norris doesn't need garbage collection because he doesn't call .Dispose(), he calls .DropKick().